<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>

	<body>
		<style>
			#contenter {
				width: 800px;
				/*border: 1px solid red;*/
			}
			
			.a {
				float: left;
				height: 500px;
				width: 20%;
				border: 1px solid green;
			}
			
			input {
				display: block;
				width: 60px;
				text-align: center;
			}
			
			input[type='button'] {
				width: 66px;
			}
			
			#a1 input {
				margin: 45px auto;
			}
			
			#a2 input {
				margin: 80px auto;
			}
			#a3 input {
				margin: 100px auto;
			}
			#a4 input {
				margin: 225px auto;
			}
		</style>
		<div id="contenter">
			<div class="a">
				<div id="a1">
					<input type="text" value="数字" />
					<input type="text" value="数字" />
					<input type="text" value="数字" />
					<input type="button" value="常量" />
					<input type="button" value="常量" />
					<input type="button" value="常量" />
					<input type="button" value="常量" />
				</div>
			</div>
			<div class="a">
				<div id="a2">
					<input type="text" value="数字" />
					<input type="text" value="数字" />
					<input type="text" value="数字" />
					<input type="button" value="常量" />
				</div>
			</div>
			<div class="a">
				<div id="a3">
					<input type="text" value="数字" />
					<input type="text" value="数字" />
					<input type="button" value="常量" />
				</div>
			</div>
			<div class="a">
				<div id="a4">
					<input type="text" value="数字" />
				</div>
			</div>
		</div>

	</body>

</html>